cold-protection for herbs

Are there herbs in your garden? When that first freeze arrives, tender annuals like basil, dill, and cardamon will die. Some perennial herbs like mint, comfrey, and anise hyssop will die back above ground, but regrow from their roots in spring. Many of these herbs will have an easier winter with help from the gardener.

How can we help our herbs survive the winter?

According to North Carolina State University, a layer of mulch will protect perennials, like mint and fennel, that die back in winter, from temperatures down around 20 degrees F. The article explains:

A winter mulch helps maintain uniform soil temperatures around the root system and provides protection against heaving cause by frequent freezing and thawing of the soil.

In other words, if your garden experiences freezing and thawing through the winter, a light layer of mulch laid around the herbs can reduce stress on their roots. That reduction in stress from freeze/thaw cycles in winter can result in healthier plants in spring.

The special case of rosemary

One herb in particular is likely to die in a harsh winter, and that is rosemary. In hardiness zone 8, and certainly in zone 9, all varieties of rosemary should survive the winter with no trouble. Where I live, zone 7b, some rosemary varieties don’t make it through the winter.

The variety in my garden is called ‘Arp’. It is the least graceful of all rosemary plants, but it is the most cold-hardy. If I were growing one of the more beautiful but less hardy varieties, I would follow NCSU’s advice: after the first hard freeze, cut the plant to a stub, just a few inches tall, then mound soil and mulch around the stub to keep it safe through winter.

The result would not be beautiful in the garden, but it might save the gardener’s budget from having to replace the rosemary next spring.

There are some happier late-autumn garden tasks than considering whether to completely cut back your rosemary bush. Mostly, these tasks are about harvesting.

Which herbs do we harvest at the end of autumn?

If there are any annual herbs left in the garden, now is the time to finish harvesting those (basil, dill, fennel, hyssop, for example). This year I grew my big crop of dill in spring, then put it all in our dehydrator (the Excaliber has a setting low enough to be safe for herbs), so we would have dill all winter. Some gardeners may have planted a late crop of dill, or they may have Holy Basil to dry for Tulsi tea. That all needs to be harvested before the weather turns truly cold.

Fading leaves of goldenseal signal that now is the time to harvest its roots.

Some gardeners, such as those in the Piedmont region, may have goldenseal, ginseng, or bloodroot ready to harvest in their woodland gardens. NCSU’s article “Harvesting and Preserving Herbs for the Home Gardener” tells us that now is the time to dig roots of these herbs — “in the fall after the foliage fades”.

Saffron crocus are up in my yard and ready for harvest, too. The flowers don’t last long, so the saffron patch needs to be checked daily. Harvest the long red thready-parts – also called the stigmas – (use tweezers), then set them on a plate or other dish somewhere safe to dry. For me, the flavor is even better if the strands are lightly toasted before using in recipes.

Saffron flowers are the source of the herb saffron, and they grow well in my yard. Now is the time to harvest the red stigmas that are the part we use in cooking.

If you don’t have any saffron growing in your garden yet, and you live only as far north as Atlanta, it is not too late to plant a patch (link to bulbs for purchase here) for next year.

Which herbs besides saffron can I plant now?

If you are counting garlic as an herb, then that is one to plant now. You actually have a pretty big window-of-opportunity for planting garlic in the Southeastern U.S., but the longer they have to grow, the bigger your garlics will be at harvest-time. See my earlier blog post about How to Plant Your Home Garden Garlic for more information.

In warmer parts of the South, late fall stretches further into November and December. In those areas, November is still a great month to plant perennial herbs (and shrubs and fruit trees!). In colder areas, plants set into the ground this late might not have a chance to get their roots into the ground before the freeze/thaw cycles begin. The risk is that the plants will get squeezed out of the ground (kind of like toothpaste out of a tube) in one of those cycles, and the roots dry out or become damaged where they are exposed to the cold.

I hope your herb garden provides the flavor and garden experience you are looking for!

(p.s. If this blog post is helpful or at all interesting, please “like” or “share” it so I will know I am on the right track. Thank you!)

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